PH-Minus in pouches allows pH values to be lowered above 7.4. The purity of its formula ensures an effective and fast action. Dosing is easy thanks to the pre-dosed bags. -Minus is a powder consisting of high purity sodium bisulphate that does not cloud the water. Derived from a strong acid, it acts effectively at high pH levels and quickly returns to the ideal pH level (between 7.0 and 7.4). pH-Minus is compatible with all treatments (bromine, active oxygen...), with all filtration systems (diatomaceous earth, cartridges, sand, glass...) and all coatings (liners, tiles, polyester). Thanks to the pre-dosed bags, its dosage is practical and fast.